My suggestion is to stay the course. This is not being reported by others, and reverting to a prior release can cause more problems.

I see. I started to downgrade but got the warning that I would have to create new profiles, so I aborted. So I will stay away from that.

New information is that the problem with with the yahoo account. If I disable yahoo, my gmail and zoho email works and I don't have the problem.

Yahoo has been setup for imap. I do leave all my messages in my inbox so I'm at the 10000 record limit for what yahoo allows to come down. It's a pain. But don't try to change me - I've been doing email this way since the beginning. Even the theading thing in Thunderbird screws me up. I need messages to appear in my inbox in time sequence. Believe it or not - it's easier for me to find them that way.

That said - any help? I've turned off yahoo email and I can do it from my phone (bluemail) in the short term - but I need it working on my desktop. It's like thunderbird is continuously downloading and windows defender is continuously checking. I've run it for hours and it doesn't cut back on the cpu useage. And worse the keyboard input is totally lagging and unresponsive.

Thanks.

Add the TB profile folder as an Exclusion in Defender settings, which is the general advice for any AV app.